An Introduction to Some Jungian Terms:
I'll try to keep this simple but it will be necessary to grasp some Jungian basics in order to understand this thread. Here's a map to help provide the reader with a snapshot of the big picture...

The Persona: For most of us, if were to try and define "who we are" we would present ourselves as our Persona. To a large extent this is the face we present to the world. It is closely related to what we call the ego -- our sense of self-identity. Our sense of self-identity arises out of our relationships with others, the roles we play and our beliefs about ourselves and the world we live in (e.g. wife, father, engineer, Christian, Democrat, easy-going, etc.) This smaller sense of identity is often referred to as the little self in Jungian psychology to differentiate it from the larger Self.
The Ego: The ego is more than just our sense of identity; it also serves as a function that separates our Persona from the remainder of the total psyche. As a function, it mediates what will be allowed to pass through from the deeper personal and collective unconscious.
The Shadow: This is the place where we store all the ugly, shameful, painful bits. In many instances, the ego will serve to keep aspects of the shadow repressed and out of consciousness, such as a past trauma or an emotion you feel ashamed of. This repressed material may relate to personal experience, cultural experience, or the collective experience of humanity. In spite of the barrier put in place by the ego, the shadow works as a very powerful force in our lives. In some cases, it is possible to become possessed by our shadow. We're going to see evidence of shadow possession in the film.
The Anima/Animus: According to Jung, every human being contains an inner being that is opposite to its exterior gender. If you are a male, this inner feminine is referred to as the anima; if you are a female, your inner masculine is referred to as the animus. We most often encounter our own anima or animus in the form of projection although the anima/animus may also make itself known through dream and fantasy.
Mana Personality: Mana personalities are very powerful archetypal patterns that are closely aligned with the Self. Historically, priests, shamans, medicine men/women, etc. have been said to represent mana personalities because they possess great, sometimes supernatural knowledge.
The Self: We could compare this part of the psyche to the sun at the center of the Universe; all psychic life flows from it -- it is the center of our psychic Universe. However, just as we once believed that the Sun revolved around the Earth, the little self sometimes suffers from the belief that the Self revolves around it! Discovering that our personas/egos are not the center of the Universe can be a very humbling, painful experience and one that most of us would prefer to avoid if at all possible.
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Now, we're going to meet the characters in the film and see where they fit upon the model above.
Jack: Jack is played by Edward Norton and serves as the narrator to the film. He corresponds with the Persona/Ego.
Tyler Durden: Tyler is played by Brad Pitt; he serves as Jack's Shadow. The larger portion of the film is focused upon this relationship between Jack as Persona/Ego and Tyler as Shadow. Tyler is a dark, ominous, even evil character yet he also adds strength to Jack's psyche and serves as an important teacher to him.
Marla Singer: This character is played by Helen Bonham Carter. Marla serves as Jack's Anima. For much of the film, Jack's (Ego)relationship to Marla (Anima) is mediated through Tyler (Shadow).
Bob: Played by Meatloaf. It's through his relationship with Bob that Jack begins to relate to his emotional life and inner turmoil. Bob serves as a Mana Personality that will help Jack come into relationship with his Self -- the true center of his psyche. It's important to note that Bob is a male who has undergone surgery and hormone treatment for testicular cancer. Like a hermaphrodite or androgynous being, these treatments have rendered him both male and female; as a result, he represents the opposites united as one.
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With those basics in place we can now turn to the movie itself with Jack serving as the narrator of his own story. Like all stories of this type we should expect that details will be jumbled and muddled together -- not even Jack understands what is happening to him. Some of the most important details are spoken as whispers or offhand comments and it can be easy to miss them but as we move through "his story" we're going to begin to understand that Jack's outer world is reliant upon his inner relationships with his Shadow, Anima and Self...
See also: Archetypes and the Individuation Process
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